EXT_SHIFT
f0 = j >> EXT_SHIFT;
f1 = (j << (32 - EXT_SHIFT)) | (k >> EXT_SHIFT);
f2 = k << (32 - EXT_SHIFT);
f0 = (frac << EXT_SHIFT) | (j >> (32 - EXT_SHIFT));
f1 = (j << EXT_SHIFT) | (k >> (32 - EXT_SHIFT));
f2 = (k << EXT_SHIFT) | (l >> (32 - EXT_SHIFT));
f3 = l << EXT_SHIFT;